Semi-Empirical Model for Nano-Scale Device Simulations

TL;DR

This paper introduces a semi-empirical model extending the Extended Hückel method with a self-consistent potential to simulate electron transport in nano-scale devices, improving agreement with experimental results.

Contribution

The paper develops a semi-empirical model that incorporates external biases and dielectric effects, enhancing the accuracy of nano-scale device simulations over previous methods.

Findings

Better agreement with experimental data than ab initio methods

Successfully models electron transport in organic molecules and graphene nanoribbons

Captures transition from tunneling to thermionic emission in transistors

Abstract

We present a new semi-empirical model for calculating electron transport in atomic-scale devices. The model is an extension of the Extended H\"uckel method with a self-consistent Hartree potential. This potential models the effect of an external bias and corresponding charge re-arrangements in the device. It is also possible to include the effect of external gate potentials and continuum dielectric regions in the device. The model is used to study the electron transport through an organic molecule between gold surfaces, and it is demonstrated that the results are in closer agreement with experiments than ab initio approaches provide. In another example, we study the transition from tunneling to thermionic emission in a transistor structure based on graphene nanoribbons.